Houston had scored only nine runs in its first five games following the All-Star break, having scored two runs in four consecutive games entering play on Wednesday.
"One thing we're going to talk about is the fact our plan at the plate has not been good," Barnett said. "I look at the swings out of the zone, and it's not good at all, and that just tells me the guys are pressing and don't have a consistent plan. When a specific situation presents itself, we've been pretty good."
The Astros are hitting a Major League-worst .153 with the bases loaded, but in the month of July, they have sent home 14 of the 21 runners they've had at third base and fewer than two outs.
"That tells me [when] the situation is in front of them, they know what they need to do ,and they fall into a plan and are executing," Barnett said. "But we can't have games where 60 percent of our swings are chasing balls out of the zone. It's tough enough to hit at this level as it is, let alone chasing that many pitches night in and night out."